The present invention relates to a path control method and apparatus which are well-suited especially for application to articulated machine tools and industrial robots having path-controlled parts (parts whose paths are to be controlled) movable within three-dimensional regions.
A path-controlled part is controlled in such a way that principal points concerning movement paths are stored as teach points in memory means in advance, and that an interpolation operation is performed by reading out the stored information. The interpolation operation becomes more complicated with increase in the number of movable axes included from a base to the path-controlled part. When industrial robots are taken as an example, recently they have five movable axes as the general trend. Further, robots of 6-axis setup are coming into wide use. Accordingly, the period of time required for the interpolation operation tends to lengthen more.
Industrial robots and machine tools are often required to perform operations for various functions, besides the operations for the path control.
The operations are executed by microcomputers in many cases. The microcomputers are inexpensive, but they do not have very high operating capabilities. In the controls of the industrial robots and machine tools, it is the actual situation that the capabilities are utilized substantially fully. On the other hand, however, it is requested to perform a preciser control by executing the interpolation operation finely and lessening the meandering of the moving path.